Drill bit with built-in cooling flow channel and drilling machine

Abstract

The invention discloses a drill bit and a drilling machine with built-in cooling flow channels, and relates to the technical field of deep hole cutting, the drill bit comprises a cutting section and a drill handle which are coaxially arranged, the drill handle is fixed above the cutting section, and the cutting section is internally provided with a through type cooling channel; the cooling channel comprises a liquid inlet flow channel formed in the drill handle and a flow channel hole which extends into the drill handle in the axial direction of the cutting section and intersects with the liquid inlet flow channel, and the tail end of the flow channel hole penetrates through the drill tip and points to the cutting area. The drill handle comprises a spline shaft, a spline sleeve and a fixing sleeve. The problems that in the prior art, a constant-pressure cooling mechanism and a static flow channel design of a drill bit cannot adapt to dynamically-changing flow resistance in deep hole machining, and consequently cooling of a cutting area fails are solved. The drill bit with the built-in cooling flow channel has the advantages that accurate synchronization of on-off of cooling liquid and cutting actions is achieved through mechanical linkage, splashing of the cooling liquid is thoroughly eradicated based on a depth self-adaptive flow control mechanism triggered by bit pressure, the service life of the drill bit is remarkably prolonged, and the drilling quality is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of deep hole cutting, in particular to a drill bit and a drilling machine with a built-in cooling channel. Background Art

[0002] During the manufacturing process of the bowl head hanging plate, pin holes need to be processed in the hanging plate body or the side wall of the bowl head seat to meet the assembly requirements of high-strength bolts or locking pins. Such deep holes must ensure the aperture accuracy, straightness and hole wall roughness, otherwise it will affect the load distribution and fatigue resistance of the hardware.

[0003] In the deep hole processing of bowl head hanging plate hardware, hole diameter accuracy, straightness and hole wall roughness are the core indicators to ensure the bolt assembly accuracy and fatigue resistance. However, the existing cooling system has a static supply mode and insufficient drill bit structure design, resulting in failure of thermal management in the cutting area, causing chain problems such as built-up edge proliferation, hole wall scratches and premature tool aging. For example, when drilling deep holes, in the existing technology, although a cooling channel is provided inside the drill bit and coolant is discharged through the outlet hole at the end of the drill bit for direct cooling, constant pressure outlet is generally used. When processing deep holes, insufficient outlet pressure will cause the coolant flow to decay exponentially with drilling depth, resulting in a sudden increase in cutting edge temperature, causing thermal runaway in the cutting area and affecting the drilling quality.

[0004] In response to the above technical problems, the present invention discloses a drill bit and a drilling machine with a built-in cooling channel. The drill bit with a built-in cooling channel in the present invention realizes the precise synchronization of the coolant on and off and the cutting action through mechanical linkage, and has a deep adaptive flow control mechanism triggered by the drilling pressure, which completely eliminates the splashing of coolant and significantly improves the drill bit life and drilling quality. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a drill bit and a drilling machine with a built-in cooling channel to solve the technical problems that the constant pressure cooling mechanism and static flow channel design of the drill bit in the existing technology cannot adapt to the dynamically changing flow resistance and heat load in deep hole processing, resulting in cooling failure in the cutting area, and ultimately endangering the assembly accuracy and fatigue resistance of the bowl head hanging plate pin hole. The drill bit with a built-in cooling channel in the present invention realizes the precise synchronization of the coolant on and off and the cutting action through mechanical linkage, and based on the depth adaptive flow control mechanism triggered by the drilling pressure, completely eliminates the splash of coolant, and significantly improves the drill bit life and drilling quality.

[0006] The present invention is achieved through the following technical solutions: The present invention discloses a drill bit with a built-in cooling channel, comprising a coaxially arranged cutting segment and a drill shank, the drill shank being fixed above the cutting segment, the cutting segment being provided with a through-type cooling channel, the cooling channel comprising a liquid inlet channel opened in the drill shank and a flow channel hole extending axially along the cutting segment into the drill shank and intersecting with the liquid inlet channel, the end of the flow channel hole penetrating the drill tip and pointing to the cutting area; The drill shank includes a spline shaft, a spline sleeve and a fixed sleeve. The fixed sleeve is coaxially fastened to the cutting section. The spline shaft is fixedly connected to the fixed sleeve. The spline sleeve is movably sleeved on the outside of the spline shaft. The liquid inlet channel includes a liquid inlet hole, a connecting hole and a shaft hole. The liquid inlet hole is opened on the side wall of the spline sleeve. The connecting hole radially penetrates the side wall of the spline shaft. The shaft hole penetrates the fixed sleeve along the axis of the spline shaft. When the spline shaft slides to a preset position under axial pressure, the connecting hole is aligned with the liquid inlet hole to form a fluid passage, and when reset, the hole is dislocated to close the flow passage.

[0007] Furthermore, a return spring is sleeved on the outside of the spline shaft, and its two ends abut the lower end surface of the spline sleeve and the upper end surface of the fixed sleeve. Under normal circumstances, the pre-pressure of the return spring drives the spline shaft to move downward to close the flow path. When drilling, the drill presses the spline shaft upward to open the flow path.

[0008] Furthermore, a limiting column is fixed at the lower end of the spline sleeve. When the drill tip contacts the workpiece and compresses the reset spring, the limiting column moves downward with the spline sleeve until it contacts the upper end surface of the fixed sleeve. At this time, the connecting hole and the liquid inlet hole are precisely aligned.

[0009] A drilling machine includes a base, a column, a workbench, a spindle system, a feed system and a drill bit with a built-in cooling channel. A rotary joint is integrated on the outside of the spline sleeve, which includes an inner shaft, an outer cylinder and a socket hole. The socket hole is opened in the center of the inner shaft to form an anti-rotation pair with the spline sleeve. The outer cylinder is supported on the outside of the inner shaft by a bearing and is rigidly connected to the drilling machine body by a fixing rod.

[0010] Furthermore, a docking hole is provided on the side wall of the outer cylinder, and a circumferential water injection groove and a radial water injection hole are opened in the middle section of the inner shaft. The water injection hole is aligned with the liquid inlet hole of the spline sleeve to form a leak-free coolant channel.

[0011] Furthermore, it also includes a liquid supply system, which includes a cooling water tank, a centrifugal pump, and a water outlet pipe. The water outlet pipe is connected to the outer cylinder docking hole through a hose, and the centrifugal pump drives the coolant to be injected into the drill bit flow channel through the rotary joint assembly.

[0012] Furthermore, a valve is installed at the connection end between the water outlet pipe and the hose, which includes a valve stem and an opening adjustment component. The opening adjustment component is linked to the downward movement depth of the drill bit through a traction component, so that the valve opening can be linearly expanded when the drilling depth increases, and the coolant pressure is dynamically matched with the bottom flow resistance of the hole.

[0013] Furthermore, the opening adjustment assembly includes a fixed shell, a gear coaxially fixed to the valve stem, a sliding seat displaced along the axial slide rail of the fixed shell, and a rack rigidly connected to the inner side of the sliding seat. The rack is engaged with the gear to convert the linear motion of the sliding seat into the rotational motion of the gear. The gear is coaxially fixed to the valve stem. A torsion spring is provided at the valve stem. Under normal circumstances, a closing torque is applied to maintain the minimum opening of the valve. When the drill bit retracts, the valve stem is driven to reset counterclockwise.

[0014] Furthermore, the traction assembly includes a traction rope and a double clamping wheel, the double clamping wheels are respectively fixed to the outer wall of the outer cylinder and the outer wall of the fixed sleeve, the traction rope is introduced from the outer edge of the upper clamping wheel, passes through the gap between the wheels, and extends from the wheel wall of the lower clamping wheel to the bottom, when the drill bit is idle, the gap between the double clamping wheels is maintained, and the traction rope slides freely; After the drill bit contacts the workpiece, the fixed sleeve moves to drive the double clamping wheels to close and engage the traction rope, converting the drill bit's downward movement into a valve opening increment.

[0015] Furthermore, the fixing rod is an axial telescopic structure to avoid interference with the downward movement of the drill bit.

[0016] The present invention has the following advantages: (1) The drill bit and drilling machine system with built-in cooling channel realizes precise synchronization of coolant on and off and cutting action through purely mechanical design. When the drill bit contacts the workpiece, the drilling pressure drives the spline shaft to slide so that the liquid inlet hole and the connecting hole are precisely aligned. The coolant is sprayed directly to the drill tip through the internal flow channel of the drill shank, directly covering the high-temperature cutting area. When the drill bit rises and resets, the reset spring pushes the spline shaft to reset and cut off the flow path, completely eliminating coolant splash pollution.

[0017] (2) The present invention is triggered by a traction component (wheel type or wedge type) responding to a drilling pressure signal. When the drill bit is idle, the traction component is decoupled and the valve maintains a minimum opening. After the drill tip contacts the workpiece, the fixed sleeve is driven by the drilling pressure displacement to drive the clamping wheel to close or the wedge to push, converting the downward displacement of the drill bit into a downward traction force of the rack. The gear overcomes the torque of the torsion spring and linearly expands the valve opening, so that the coolant flow rate is proportional to the incremental drilling depth. The flow rate is increased in the deep hole stage to ensure chip removal efficiency and drill tip cooling, and high-pressure splashing is suppressed in the shallow hole stage. After drilling is completed, the traction force is released, the torsion spring drives the valve to reset and close and simultaneously cuts off the cooling flow path, thereby improving processing stability and drill bit life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the drill bit structure of the present invention; Figure 2 It is a schematic diagram of the cutting segment structure of the present invention; Figure 3 This is a schematic diagram of the drill handle structure of the present invention; Figure 4 This is a schematic diagram of the cross-sectional structure of the drill shank of the present invention; Figure 5 This is a schematic cross-sectional view of the rotary joint of the present invention; Figure 6 It is a schematic diagram of the overall structure of the drilling machine of the present invention; Figure 7 It is a structural schematic diagram of the drilling machine and the liquid supply system of the present invention; Figure 8 For the present invention Figure 7A schematic diagram of the partially enlarged structure at point C; Figure 9 For the present invention Figure 6 A local enlarged structural diagram of point A; Figure 10 For the present invention Figure 6 A schematic diagram of the partially enlarged structure at point B; Figure 11 Schematic diagram of the structure of the opening adjustment component of the present invention; Figure 12 For the present invention Figure 9 A schematic diagram of the local enlarged structure at D; Figure 13 It is a structural schematic diagram of the drilling machine and the wedge-type traction assembly of the present invention; Figure 14 For the present invention Figure 13 Schematic diagram of the local enlarged structure at E; Figure 15 This is a schematic diagram of the cross-sectional structure of the clamping block of the present invention.

[0019] In the figure: 1. Drilling machine; 2. Drill bit; 3. Cooling channel; 4. Liquid supply system; 5. Positioning plate; 6. Limit plate; 7. Return spring; 8. Limit column; 9. Rotary joint; 10. Connecting rod; 11. Large diameter section; 12. Water injection groove; 13. Water injection hole; 14. Docking hole; 15. Connecting joint; 16. Valve; 17. Opening adjustment assembly; 18. Wheel traction assembly; 19. Wedge traction assembly; 101. Base; 102. Column; 103. Workbench; 104. Spindle system; 105. Feed system; 201. Cutting section; 202. Drill shank; 401. Cooling water tank; 402. Pumping unit; 421. Centrifugal pump. 422. Water inlet pipe; 423. Water outlet pipe; 221. Spline shaft; 222. Spline sleeve; 223. Fixed sleeve; 301. Liquid inlet channel; 302. Channel hole; 311. Liquid inlet hole; 312. Connecting hole; 313. Shaft hole; 901. Inner shaft; 902. Socket hole; 903. Outer cylinder; 171. Fixed shell; 172. Gear; 173. Sliding seat; 174. Rack; 181. Traction rope; 182. Double clamping wheel; 183. Fixed rod; 191. Traction rod; 192. Clamping block; 193. Wedge block unit; 194. Guide groove; 195. Clamping plate; 196. Spring group; 197. Guide rod; 198. Guide wheel. DETAILED DESCRIPTION

[0020] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, and a detailed implementation method and specific operation process are given. However, the scope of protection of the present invention is not limited to the following embodiment. In the description of the present invention, words indicating directions or positional relationships such as "front", "rear", "left", and "right" are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as a limitation on the present invention.

[0021] The embodiment discloses a drill bit with a built-in cooling channel, such as Figures 1-15 As shown, the drill bit 2 is composed of a coaxially arranged cutting segment 201 and a drill shank 202. Figure 1-Figure 3 As shown, the drill shank 202 is fixed above the cutting section 201 .

[0022] like Figure 1-Figure 4 As shown, a through-type cooling channel 3 is provided inside the cutting segment 201, and the cooling channel 3 includes a liquid inlet channel 301 and a channel hole 302, wherein the liquid inlet channel 301 is opened inside the drill shank 202, and one end passes through the side wall of the drill shank 202, and the channel hole 302 extends along the axial center of the cutting segment 201 to the inside of the drill shank 202, and intersects with the liquid inlet channel 301 to form a fluid passage, and the end of the channel hole 302 corresponds to the drill tip position of the cutting segment 201. It passes through the outer wall of the cutting segment 201 and points to the cutting area. During operation, the coolant is injected through the liquid inlet channel 301, flows axially along the axial hole 313, and is discharged from the end of the channel hole 302, thereby realizing cooling of the cutting area. The coolant is sprayed from the drill tip and directly acts on the high-temperature area of ​​the cutting edge. In addition, the coolant absorbs the heat conducted by the cutting segment 201 during the process of flowing through the axial hole 313, thereby realizing temperature control inside the tool.

[0023] It should be noted that the cooling channel 3 can be optimized to be a spiral conformal cooling channel 3, which precisely matches the spiral trajectory of the chip groove of the drill bit 2, penetrates the drill tip at the end and opens a liquid outlet. By increasing the flow channel length, the heat exchange area between the coolant and the drill body is significantly increased to achieve axial cooling.

[0024] In batch drilling operations on hanging plates, operators usually clamp multiple workpieces at a time. After completing the drilling of a single piece, they release the rocker to raise the sleeve, and the drill bit 2 is reset. At this time, the operator quickly replaces the next hanging plate and aligns it with the drill bit 2, and then continues drilling. To improve processing efficiency, the spindle of the drilling machine 1 continues to operate and the coolant supply system also remains on. However, this process has the problem that when the drill bit 2 rises and resets, the continuously sprayed coolant is thrown out with the rotation of the drill bit 2, causing splash pollution.

[0025] To this end, this embodiment is designed through the structure of the drill shank 202 to close the liquid inlet channel 301 during the non-cutting stage, thereby completely preventing the splashing of coolant.

[0026] Specifically, such as Figure 1-Figure 4 As shown, the drill shank 202 includes a spline shaft 221, a spline sleeve 222 and a fixed sleeve 223. The end of the cutting segment 201 is inserted into the inner cavity of the fixed sleeve 223 and is coaxially fastened in the fixed sleeve 223 by a high-strength screw. The spline shaft 221 is integrally connected to the top of the fixed sleeve 223, and its outer diameter is smaller than the fixed sleeve 223. The spline sleeve 222 is movably sleeved on the outside of the spline shaft 221, and the top of the spline shaft 221 is fixed to the limit plate 6 by a fastening screw, and the outer diameter of the limit plate 6 is larger than the inner diameter of the spline sleeve 222, forming a hard limit barrier to prevent the spline pair from separating, and the spline sleeve 222 is fixed by the chuck of the drilling machine 1. When cutting and drilling, the spindle drives the spline sleeve 222 to rotate, and the spline shaft 221 is driven to rotate synchronously through the involute spline engagement. The spline shaft 221 drives the fixed sleeve 223 to rotate and drives the cutting segment 201 to perform cutting.

[0027] Correspondingly, the liquid inlet channel 301 includes a liquid inlet hole 311, a connecting hole 312 and a shaft hole 313, wherein the liquid inlet hole 311 is radially opened along the spline sleeve 222 and passes through its inner cavity wall and outer wall, directly connecting to the external coolant supply pipeline, and the connecting hole 312 is radially distributed along the spline shaft 221 and passes through the outer wall of the spline shaft 221. When the spline shaft 221 slides axially to the preset position, the connecting hole 312 is coaxially aligned with the liquid inlet hole 311 to form a fluid interface.

[0028] The shaft hole 313 passes through the axis of the spline shaft 221 , extends from the inner cavity communication hole 312 of the spline shaft 221 to the top wall of the fixing sleeve 223 and connects to the inner cavity thereof, and finally coaxially communicates with the internal flow channel hole 302 of the cutting segment 201 .

[0029] In the non-cutting state, the connecting hole 312 and the liquid inlet hole 311 are offset up and down, and the flow channel is completely closed. When entering the cutting state, when the cutting segment 201 is driven by axial pressure to drive the spline shaft 221 to slide in the inner cavity of the spline sleeve 222, the connecting hole 312 and the liquid inlet hole 311 are precisely aligned, the coolant forms a complete passage through the liquid inlet hole 311, the connecting hole 312, the shaft hole 313, and the flow channel hole 302 of the cutting segment 201, and is ejected to the cutting area. When resetting, the spline shaft 221 slides in the opposite direction, the channel is misaligned and the flow path is cut off, thereby realizing synchronization of coolant injection and cutting action.

[0030] Optionally, a fluororubber sealing ring may be nested in the joint area between the communicating hole 312 and the liquid inlet hole 311 , and the inner cavity of the spline sleeve 222 and the outer surface of the spline shaft 221 may be plated with a wear-resistant layer, such as a hard chrome plating layer.

[0031] In addition, if Figure 6 and Figure 7As shown, a return spring 7 is sleeved on the outside of the spline shaft 221, and its two ends respectively abut the lower end surface of the spline sleeve 222 and the upper end surface of the fixed sleeve 223. Under normal conditions, the pre-pressure of the return spring 7 drives the spline shaft 221 to move downward, causing the connecting hole 312 and the liquid inlet hole 311 to be axially misaligned. At this time, the entrance of the liquid inlet hole 311 is completely blocked by the outer wall of the spline shaft 221, and the coolant passage is forcibly cut off.

[0032] During drilling operation, the spindle drives the drill bit 2 downward, and the drill tip is blocked after contacting the workpiece. Then the spindle continues to press down to overcome the spring resistance, causing the spline shaft 221 to slide upward relative to the spline sleeve 222, so that the connecting hole 312 and the liquid inlet hole 311 are precisely aligned. Therefore, the coolant forms a complete passage through the liquid inlet hole 311, the connecting hole 312, and the shaft hole 313 and is ejected into the cutting area.

[0033] During the drilling process, the downward pressure of the spindle continuously maintains the alignment of the channel to ensure a stable supply of coolant. After the drilling is completed, the drill bit 2 moves up, and the spring pre-pressure is instantly released to drive the spline shaft 221 to move down and reset. After that, the channel is dislocated and the valve is closed, and the coolant is cut off synchronously, completely avoiding the splashing of liquid when the drill bit 2 rises and rotates.

[0034] In order to achieve precise control of the downward movement of the spline sleeve 222, as Figure 1 As shown, a limiting column 8 structure is additionally provided, and the limiting column 8 is fixedly connected to the lower end of the spline sleeve 222. When the drill tip contacts the workpiece and overcomes the spring preload, the spline sleeve 222 slides downward along the spline shaft 221, and the limiting column 8 moves downward therewith until the lower end surface of the limiting column 8 contacts the upper end surface of the fixed sleeve 223. At this time, the connecting hole 312 and the liquid inlet hole 311 are coaxially aligned, and the coolant passage is connected.

[0035] Through the above arrangement, the coolant injection is synchronized with the cutting action, avoiding the splashing of liquid when the drill bit 2 rises and rotates, which may cause pollution. At the same time, the coolant is only supplied during the cutting period, which can effectively save the coolant consumption rate compared with continuous liquid supply.

[0036] like Figure 6-Figure 9As shown, this embodiment also discloses a drilling machine, which includes the drill bit 2 with built-in cooling channel in the above embodiment, and also includes a base 101, a column 102, a workbench 103, a spindle system 104 and a feed system 105. The base 101 has a built-in electrical control unit and bears the load of the entire machine. The column 102 is vertically fixed to the base 101 to provide a rigid guide for the lifting movement of the drill bit 2. The workbench 103 is used for rigid clamping of the bowl head hanging plate workpiece to ensure that the machining reference surface is coaxial with the spindle axis. The spindle system 104 It includes a variable frequency motor, a tower pulley and a sleeve-type spindle. The motor drives the spindle to rotate through the variable speed pulley. The spindle is nested in a sleeve with a rack 174. It can rotate freely but rises and falls synchronously with the sleeve. The drill bit 2 is installed at the end of the spindle through a chuck and is directly driven by the spindle to rotate and cut. The feed system 105 is driven by a manually operated rocker. The rotational motion of the rocker is converted into a longitudinal linear feed of the sleeve through the gear 172 and the rack 174 mechanism. The staff manipulates the rocker to make the spindle sleeve drive the drill bit 2 to descend to complete the deep hole drilling process.

[0037] In order to achieve accurate and automatic liquid supply to the liquid inlet channel 301, a liquid supply system 4 is also integrated. The system consists of a cooling water tank 401 and a pumping unit 402 to form a closed fluid circuit. The cooling water tank 401 adopts a double-layer stainless steel structure. The pumping unit 402 includes a centrifugal pump 421, an inlet pipe 422 and an outlet pipe 423. The centrifugal pump 421 is fixed on the top of the water tank, and its water inlet extends below the liquid level of the water tank through the inlet pipe 422. The water outlet is connected to the outlet pipe 423. The end of the outlet pipe 423 is connected to the liquid inlet channel 301 of the drill shank 202 through a connecting joint to form a leak-free fluid channel. During the cutting process, the coolant is extracted by the centrifugal pump 421, injected into the liquid inlet channel 301 of the drill shank 202 through the outlet pipe 423, and finally sprayed out from the drill tip spray hole to cover the cutting area.

[0038] To continuously supply coolant to the high-speed rotating drill shank 202, Figure 5-Figure 9 As shown, a rotary joint 9 is integrated onto the exterior of the splined sleeve 222. The joint's inner shaft 901 is designed with an axially extending sleeve bore 902, into which the splined sleeve 222 is directly inserted. A dynamic sliding seal is achieved between the splined sleeve 222's outer wall and the inner wall of the sleeve bore 902 via a PTFE sealing ring or wear-resistant ceramic ring. A dual-ball bearing support structure is employed within the rotary joint 9, ensuring smooth operation and reliable sealing even at high speeds. Furthermore, the rotary joint 9 is rigidly connected to the drilling machine 1 via a rigid fixing rod 10, forming a stable static support system. This effectively isolates the sealing interface from drilling vibrations and ensures leak-free transmission of high-pressure coolant at high speeds.

[0039] like Figure 5As shown, the rotary joint 9 assembly utilizes a coaxial sleeve structure, comprising an inner shaft 901, a sleeve bore 902, and an outer cylinder 903. The sleeve bore 902 extends axially through the center of the inner shaft 901, forming a dynamic fit with the splined sleeve 222. The top of the splined sleeve 222 extends through the upper end face of the inner shaft 901, and its extension is rigidly clamped by a chuck. The top end of the inner shaft 901 abuts against the flat bottom face of the chuck, forming an axial limit. The outer cylinder 903 is coaxially sleeved to the exterior of the inner shaft 901 via double-row angular contact bearings, achieving relative rotational freedom. PTFE stepped sealing rings or silicon carbide mechanical seals are installed at the junction of the upper and lower sections of the inner shaft 901 and the outer cylinder 903 to maintain rotational sealing and simultaneously prevent coolant leakage.

[0040] The middle section of the inner shaft 901 is designed as a large-diameter structure, and dynamic sealing is achieved between its outer circumference and the inner wall of the outer cylinder 903 through a stepped sealing ring; the large-diameter section 11 is precisely positioned between the inner shaft 901 and the upper and lower bearing seats of the outer cylinder 903 to form an axial constraint.

[0041] A circumferential water injection groove 12 is formed in an annular concave shape on the outer wall of the middle section of the large diameter section 11, and a water injection hole 13 is radially passed through the bottom of the groove to connect to the inner cavity of the sleeve hole 902; synchronously, a docking hole 14 is radially formed at the corresponding position of the wall of the outer cylinder 903, so that the docking hole 14, the water injection groove 12, the water injection hole 13, and the sleeve hole 902 constitute a four-level through flow channel.

[0042] The cross section of the sleeve hole 902 adopts a composite configuration of a round bottom and straight edges, and a keyway-type straight edge is axially provided on its inner wall to form a circumferential anti-rotation pair with the corresponding straight edge on the outer wall of the spline sleeve 222, completely preventing relative rotation. Figure 4 As shown, when the spline sleeve 222 is inserted, its bottom flange positioning plate 5 abuts against the bottom plane of the inner shaft 901 to achieve axial hard positioning; at this time, the liquid inlet hole 311 on the side wall of the spline sleeve 222 is precisely aligned with the water injection hole 13 of the inner shaft 901, and a fluororubber O-ring sealing interface is set on the docking surface to form a leak-free transfer channel for the coolant.

[0043] The liquid supply system 4 of the high-pressure rotary joint 9 realizes the tangle-free transmission of the coolant through structural linkage: the main shaft of the drilling machine 1 drives the spline sleeve 222 to rotate, and the straight edge of the outer wall of the spline sleeve 222 and the straight edge of the sleeve hole 902 of the inner shaft 901 form a circumferential interlocking anti-rotation pair, which synchronously drives the inner shaft 901 to rotate; the outer cylinder 903 is supported on the outside of the inner shaft 901 by a double-row angular contact bearing, and is rigidly connected to the body of the drilling machine 1 through the fixing rod 10, forming a static constraint system, completely isolating the rotational freedom.

[0044] The coolant is injected into the annular water injection groove 12 through the radial docking hole 14 of the outer cylinder 903, and is accurately introduced into the inner cavity of the spline shaft 221 through the through-flow channel that is dynamically aligned with the water injection hole 13 of the inner shaft 901 and the liquid inlet hole 311 of the spline sleeve 222, thereby realizing a constant flow of coolant supply under the high-speed rotation condition of the main shaft. In addition, the external water pipe completely avoids the risk of entanglement because the outer cylinder 903 is statically fixed.

[0045] It should be noted that the fixing rod 10 is configured as an axially telescopic structure, thereby avoiding affecting the downward movement of the drill bit 2.

[0046] like Figure 6-Figure 9 As shown, the outlet pipe 423 of the cooling water tank 401 extends through a hose to the docking hole 14 of the outer cylinder 903, and fluid docking is achieved through the connecting joint 15; when the centrifugal pump 421 is started, the coolant is injected from the water tank through the outlet pipe 423 and the connecting joint 15 into the flow channel of the docking hole 14 to supply the drill bit 2.

[0047] In view of the pressure adaptation contradiction of the constant pressure pump under the condition of variable hole depth, the high-pressure coolant in the shallow hole stage is prone to cause energy redundancy and splash loss, while the low-pressure coolant in the deep hole stage causes poor chip removal and sintering of the drill bit 2. In this embodiment, Figure 10 As shown, by setting a valve 16 at one end of the water outlet pipe 423, the water output is controlled by opening the valve port of the valve 16, and the opening adjustment of the valve 16 is set to be controlled by the downward movement of the drill bit 2, thereby achieving the matching of the coolant pressure and the drilling depth throughout the drilling process, eliminating energy waste and cooling blind spots in the constant pressure liquid supply mode.

[0048] Specifically, such as Figure 10 and Figure 11 As shown, a valve 16 is installed at the connection end between the water outlet pipe 423 and the hose, and the coolant flow is precisely regulated by the valve 16; and an opening adjustment component 17 is provided at the valve stem of the valve 16, the core of which is a gear 172 rack 174 type opening adjustment component 17, which includes a fixed shell 171, a gear 172, a sliding seat 173 and a rack 174.

[0049] The opening adjustment of the opening adjustment component 17 is controlled by the downward movement of the traction component and the drill bit 2, thereby achieving a precise match between the coolant pressure and the bottom hole flow resistance throughout the drilling process.

[0050] Among them, the fixed shell 171 is rigidly installed on the valve stem base of the valve 16, and the gear 172 and the valve stem are coaxially fixed inside the shell to form a rotational motion coupling pair; the sliding seat 173 moves along the axial slide rail of the fixed shell 171, and its inner side is rigidly connected to the rack 174, forming a linear and rotational motion conversion pair with the gear 172.

[0051] In addition, a torsion spring (not shown in the figure) is provided at the valve stem or gear 172 for elastic reset. The valve stem reset mechanism of the torsion spring preload is specifically as follows: under normal conditions, the torsion spring applies a closing torque to maintain the minimum opening of the valve 16; when the traction assembly responds to the downward movement of the drill bit 2 to drive the rack 174 downward, the gear 172 rotates and overcomes the torsion spring torque, driving the valve stem to rotate synchronously to linearly expand the valve opening; as the drilling depth increases, the displacement of the rack 174 is proportional to the opening of the valve 16, realizing dynamic matching of the coolant pressure and the bottom flow resistance of the hole, and when the drill bit 2 retracts, the traction force is released, the torsion spring releases the stored energy to drive the valve stem to reset counterclockwise, synchronously driving the gear 172 to reverse and the rack 174 to move upward, and the opening of the valve 16 is converged to the initial state, forming a closed-loop control.

[0052] This embodiment also addresses the problem of premature adjustment of valve 16 opening during the idle stroke of drill bit 2, leading to a mismatch between drilling depth and pressure. A contact-triggered traction control mechanism is designed. This mechanism ensures that the traction assembly responds to the downward movement of drill bit 2 and drives valve 16 opening adjustment only when drill bit 2 contacts the workpiece surface and enters an effective cutting state. The moment drill bit 2 contacts the workpiece surface, cutting resistance triggers the traction assembly. The incremental downward movement of drill bit 2 is then linearly converted to incremental valve 16 opening via the gear 172 and rack 174 conversion pair, achieving real-time and precise matching of drilling depth and coolant pressure.

[0053] like Figure 6 、 Figure 9 and Figure 12 As shown, the traction assembly integrates a contact-triggered clamping mechanism. In this embodiment, the traction assembly is a wheeled traction assembly 18, which includes a traction rope 181 and a double clamping wheel 182. The end of the traction rope 181 is fixed to the bottom end of the sliding seat 173, and the two clamping wheels are arranged longitudinally coaxially with a preset initial spacing between the wheels. The path of the traction rope 181 is designed to be introduced from the outer edge of the upper clamping wheel, pass through the gap between the wheels, and extend from the wheel wall of the lower clamping wheel to the bottom; the two clamping wheels are anchored to the outer wall of the outer cylinder 903 and the outer wall of the fixed sleeve 223 through a rigid fixing rod 183, respectively, to form a spatial floating support structure.

[0054] During the downward movement stage of the drill bit 2 in the idle stroke, a safe distance is maintained between the fixed sleeve 223 and the outer cylinder 903 (without resistance from the workpiece), the wheel gap of the clamping wheels is maintained at a preset value, the traction rope 181 freely passes through the gap without effective traction output, and the rack 174 remains stationary; when the drill bit 2 contacts the workpiece and applies drilling pressure, the cutting reaction force drives the spline shaft 221 to slide in the spline sleeve 222, compressing the reset spring 7, and the fixed sleeve 223 synchronously moves axially toward the outer cylinder 903 until the fixed sleeve 223 forms a hard limit coupling with the spline sleeve 222 through the limit column 8; at this time, the two clamping wheels are driven radially to close by the displacement of the fixed sleeve 223, and the clamping force of the wheel surface bites the outer wall of the traction rope 181, converting the downward displacement of the drill bit 2 into a linear traction force of the traction rope 181, which overcomes the pre-tightening torque of the torsion spring of the valve 16, drives the rack 174 downward and triggers the valve 16 to open wider, thereby realizing dynamic matching of the coolant pressure and the drilling depth. This design ensures that the pressure regulation action only occurs during the effective cutting stage, avoiding pressure mismatch caused by false triggering of the idle stroke.

[0055] In addition, optionally, in other embodiments, Figure 13-15 As shown, the traction assembly can be replaced with a wedge-type traction assembly 19, which includes a traction rod 191, a clamping block 192 and a wedge unit 193. The traction rod 191 is rigidly fixed to the bottom end of the sliding seat 173, and a rectangular guide groove 194 is longitudinally penetrated inside the clamping block 192. The traction rod 191 is fully arranged in the guide groove 194; a clamping plate 195 is arranged on the internal transverse slide rail of the clamping block 192, and the clamping plate 195 is normally maintained in the non-interference position of the guide groove 194 by the pre-tightening force of the spring group 196, so as to ensure that the traction rod 191 can slide freely; the clamping block 192 is laterally slidably assembled with a guide rod 197, and the end of the guide rod 197 is hinged to the guide wheel 198, and the clamping block 192 is anchored to the outer wall of the outer cylinder 903 through the bracket; the outer wall of the fixing sleeve 223 is fixed with the wedge unit 198, and the wedge inclined surface is in rolling contact with the guide wheel 198 and the inclination angle is optimized.

[0056] When the drill bit 2 is in the idle stroke stage, the fixed sleeve 223 maintains a distance from the outer cylinder 903, the wedge block is in a low position, the guide wheel 198 is pre-tightened by the spring and abuts against the base end of the wedge block's inclined surface, and the clamping plate 195 is away from the traction rod 191 inside the guide groove 194; after the drill bit 2 contacts the workpiece, the fixed sleeve 223 is driven by the drilling pressure to move axially, and the wedge block moves upward synchronously. Its inclined surface pushes the guide wheel 198 to move laterally and compresses the spring group 196, forcing the clamping plate 195 to radially lock the traction rod 191 in the guide groove 194, forming a rigid traction coupling; at this time, the downward displacement of the drill bit 2 is converted into a downward movement of the sliding seat 173 through the clamping block 192 and the traction rod 191, driving the rack 174 to overcome the torsional spring torque of the valve 16 and linearly expand the opening, thereby realizing dynamic matching of the coolant pressure and the drilling depth. When the drill bit 2 retreats, the wedge moves downward, the spring group 196 releases energy to push the clamping plate 195 to reset, the traction rod 191 resumes the free sliding state, and the opening of the valve 16 is synchronously tightened.

[0057] The principle of the present invention is as follows: when the drill bit 2 contacts the workpiece, the drilling pressure drives the spline shaft 221 to overcome the pre-pressure of the return spring 7 and slide upward, so that the connecting hole 312 on the side wall of the spline shaft 221 is accurately aligned with the liquid inlet hole 311 of the spline sleeve 222, and the coolant forms a complete passage through the liquid inlet hole 311 → connecting hole 312 → shaft hole 313 → flow channel hole 302 of the cutting section 201, and is sprayed from the drill tip to cover the cutting area; at this time, the rotary joint 9 assembly is connected to the workpiece through the static outer cylinder 903 The decoupling design of the dynamic inner shaft 901 ensures leakage-free transmission of high-pressure coolant. The outer cylinder 903 supports the inner shaft 901 through double-row angular contact bearings and is rigidly fixed to the body of the drilling machine 1 through the telescopic fixing rod 10. The inner shaft 901 rotates synchronously with the spline sleeve 222 through the keyway anti-rotation pair. The coolant is injected into the circumferential water injection groove 12 of the inner shaft 901 through the docking hole 14 of the outer cylinder 903, and then dynamically penetrates through the radial water injection hole 13 and the liquid inlet hole 311 of the spline sleeve 222 to be introduced into the flow channel of the drill shank 202. As the drilling depth increases, the contact-triggered traction assembly (double clamping wheels 182 or wedge mechanism) responds to the drilling pressure signal and is activated. When the drill bit 2 is in an idle stroke, the traction assembly is in a decoupled state. When the drill tip contacts the workpiece, the fixed sleeve 223 is driven by the drilling pressure to move axially, forcing the clamping wheel to close and engage the traction rope 181 or the wedge to push the clamping block 192 to lock the traction rod 191, converting the downward displacement of the drill bit 2 into a downward traction force of the rack 174, driving the gear 172 to rotate and overcome the torsion spring torque of the valve 16 to linearly expand the opening, so that the coolant flow is proportional to the hole depth, solving the contradiction between splashing in shallow holes and insufficient cooling in deep holes. After drilling is completed, the drill bit 2 rises, and the return spring 7 pushes the spline shaft 221 downward to cause the connecting hole 312 and the liquid inlet hole 311 to be misaligned and cut off the flow path. At the same time, the traction force is released, and the torsion spring drives the valve 16 to close to its initial opening, completely eliminating the rising and splashing of the coolant.

[0058] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A drill bit with a built-in cooling channel, comprising a coaxially arranged cutting section (201) and a drill shank (202), wherein the drill shank (202) is fixed above the cutting section (201), and is characterized in that: A through-type cooling channel (3) is provided inside the cutting section (201), the cooling channel (3) comprising a liquid inlet channel (301) opened inside the drill shank (202) and a flow channel hole (302) extending axially along the cutting section (201) to the inside of the drill shank (202) and intersecting with the liquid inlet channel (301), the end of the flow channel hole (302) passing through the drill tip and pointing to the cutting area; The drill shank (202) comprises a spline shaft (221), a spline sleeve (222) and a fixed sleeve (223); the fixed sleeve (223) is coaxially fastened to the cutting section (201); the spline shaft (221) is fixedly connected to the fixed sleeve (223); and the spline sleeve (222) is movably sleeved on the outside of the spline shaft (221); The liquid inlet channel (301) comprises a liquid inlet hole (311), a communication hole (312), and an axial hole (313); the liquid inlet hole (311) is formed on the side wall of the spline sleeve (222); the communication hole (312) radially penetrates the side wall of the spline shaft (221); and the axial hole (313) extends along the axis of the spline shaft (221) to the fixed sleeve (223); When the spline shaft (221) slides to a preset position under axial pressure, the communication hole (312) is aligned with the liquid inlet hole (311) to form a fluid passage, and when reset, the hole is dislocated to close the flow passage.

2. A drill bit with a built-in cooling channel according to claim 1, characterized in that: The spline shaft (221) is externally sleeved with a return spring (7), the two ends of which abut against the lower end surface of the spline sleeve (222) and the upper end surface of the fixed sleeve (223). Under normal conditions, the preload of the return spring (7) drives the spline shaft (221) downward to close the flow path. When drilling, the drill presses the spline shaft (221) upward to open the flow path.

3. The drill bit with built-in cooling channel according to claim 1, characterized in that: The lower end of the spline sleeve (222) is fixed with a limiting column (8). When the drill tip contacts the workpiece and compresses the reset spring (7), the limiting column (8) moves downward along with the spline sleeve (222) until it contacts the upper end surface of the fixed sleeve (223). At this time, the connecting hole (312) and the liquid inlet hole (311) are precisely aligned.

4. A drilling machine, comprising a base (101), a column (102), a workbench (103), a spindle system (104), a feed system (105), and a drill bit with a built-in cooling channel according to any one of claims 1 to 3, characterized in that: The spline sleeve (222) is externally integrated with a rotary joint (9), which comprises an inner shaft (901), an outer cylinder (903), and a sleeve hole (902). The sleeve hole (902) is provided at the center of the inner shaft (901) and forms an anti-rotation pair with the spline sleeve (222). The outer cylinder (903) is supported on the outside of the inner shaft (901) via a bearing and is rigidly connected to the body of the drilling machine (1) via a fixing rod (10).

5. A drilling machine according to claim 4, characterized in that: The side wall of the outer cylinder (903) is provided with a docking hole (14), and the middle section of the inner shaft (901) is provided with a circumferential water injection groove (12) and a radial water injection hole (13). The water injection hole (13) is aligned with the liquid inlet hole (311) of the spline sleeve (222) to form a leak-proof cooling liquid channel.

6. A drilling machine according to claim 4, characterized in that: The invention also includes a liquid supply system (4), the liquid supply system (4) including a cooling water tank (401), a centrifugal pump (421), and a water outlet pipe (423), the water outlet pipe (423) being connected to the docking hole (14) of the outer cylinder (903) via a hose, and the centrifugal pump (421) driving the coolant to be injected into the flow channel of the drill bit (2) through the rotary joint (9) assembly.

7. A drilling machine according to claim 6, characterized in that: The outlet pipe (423) is connected to the hose by a valve (16), which includes a valve stem and an opening adjustment component (17). The opening adjustment component (17) is linked to the downward movement depth of the drill bit (2) through a traction component, so that the opening of the valve (16) is linearly expanded when the drilling depth increases, and the coolant pressure is dynamically matched with the bottom hole flow resistance.

8. A drilling machine according to claim 7, characterized in that: The opening adjustment assembly (17) includes a fixed shell (171), a gear (172) coaxially fixed to the valve stem of the valve (16), a sliding seat (173) displaced along the axial slide rail of the fixed shell (171), and a rack (174) rigidly connected to the inner side of the sliding seat (173). The rack (174) is engaged with the gear (172) to convert the linear motion of the sliding seat (173) into the rotational motion of the gear (172). The gear (172) is coaxially fixedly connected to the valve stem of the valve (16). A torsion spring is provided at the valve stem, which applies a closing torque under normal conditions to maintain the minimum opening of the valve (16). When the drill bit (2) retracts, the valve stem is driven to reset counterclockwise.

9. A drilling machine according to claim 7, characterized in that: The traction assembly comprises a traction rope (181) and a double clamping wheel (182), wherein the double clamping wheel (182) is fixed to the outer wall of the outer cylinder (903) and the outer wall of the fixed sleeve (223), respectively. The traction rope (181) is introduced from the outer edge of the upper clamping wheel, passes through the gap between the wheels, and extends from the wheel wall of the lower clamping wheel to the bottom. When the drill bit (2) is in an idle stroke, the gap between the double clamping wheels (182) is maintained, and the traction rope (181) slides freely. After the drill bit (2) contacts the workpiece, the fixed sleeve (223) moves to drive the double clamping wheels (182) to close and engage the traction rope (181), thereby converting the downward movement of the drill bit (2) into an increase in the opening degree of the valve (16).

10. A drilling machine according to claim 4, characterized in that: The fixing rod (10) is an axial telescopic structure to avoid interference with the downward movement of the drill bit (2).

Images